Tool

Email validator built for forms, bulk CSV, and APIs.

Classify valid, invalid, risky, and unknown recipients with 12-layer syntax, DNS, MX, SMTP, catch-all, disposable, role, typo, confidence, and suppression evidence.

Validate an email Validation API

validation layers

clear outcomes

CSV + API

workflows

Validation is a policy decision, not a yes/no sticker

Some domains accept every SMTP probe, some block probes, and some addresses are technically valid but risky for bulk sending. WillItInbox separates valid, invalid, risky, catch-all, disposable, role, typo, and unknown evidence so your product or campaign can choose the right action.

Result	What it means	Typical action
valid	Evidence suggests the mailbox can receive mail.	Accept, but keep monitoring bounces.
invalid	Syntax, DNS, MX, or mailbox evidence fails.	Suppress before sending.
risky	Catch-all, role, disposable, or policy signals need context.	Segment or review before volume.
unknown	The provider did not produce reliable evidence.	Retry later or send conservatively.

Twelve layers produce four honest outcomes

The validator combines cheap deterministic checks with bounded network evidence. It never turns an SMTP acceptance into a promise that a person exists or that a future message will reach the inbox.

Layer group	Examples	Decision value
Address and domain	Syntax, normalization, DNS, MX, and null-MX handling.	Reject structurally impossible or non-receiving addresses early.
Mailbox evidence	Bounded SMTP, provider behavior, and catch-all probing.	Separate confirmed failures from inconclusive provider responses.
Risk classification	Disposable, role, typo, provider, confidence, and suppression signals.	Apply product or campaign policy without losing the underlying evidence.

Where the validator fits

Use the same evidence model wherever addresses enter your system: signup, lead capture, imports, outbound lists, support tools, enrichment jobs, and reactivation campaigns.

Forms

Reduce typos and obvious bad addresses before they become product records.

Bulk CSV

Upload stale or imported lists, download enriched results, and keep original rows intact.

API

Build validation into signup, CRM, lead, or internal QA workflows.

Workflow graphic

A 12-layer validation workflow built for decisions

The validator is not a decorative score. It walks through cheap deterministic checks, domain evidence, bounded network signals, risk classifiers, and suppression policy so the next action is obvious.

Stage	Evidence	Decision output
1. Normalize	Syntax, casing, IDN handling, malformed local parts, obvious typos.	Reject impossible addresses early or attach a suggested correction.
2. Resolve	DNS, MX, null-MX, provider family, and receiving-domain posture.	Separate non-receiving domains from addresses worth deeper checks.
3. Probe carefully	Bounded SMTP evidence, provider behavior, temporary failures, and catch-all probes.	Trust confirmed failures, but keep provider-blocked or greylisted evidence as unknown.
4. Classify risk	Disposable, role, catch-all, typo, suppression, and confidence signals.	Return valid, invalid, risky, or unknown with a reason and recommended action.

Decision matrix

Valid, invalid, risky, and unknown should not be treated the same

Competitor pages often collapse nuance into pass or fail. WillItInbox keeps the business decision separate from the evidence so growth, product, and ops teams can tune policy without losing accuracy.

Status	Example reasons	Recommended policy
valid	Syntax passes, receiving domain exists, mailbox evidence is acceptable.	Accept, enrich, or send while still monitoring bounces and complaints.
invalid	Bad syntax, no receiving mail service, rejected mailbox, or hard failure.	Suppress before sending and keep the reason for audit/debugging.
risky	Catch-all, role account, disposable provider, or low-confidence evidence.	Segment, lower volume, require confirmation, or route to manual review.
unknown	Temporary SMTP failure, provider block, greylisting, timeout, or inconclusive evidence.	Retry later, wait for follow-up evidence, or send conservatively only when consent is strong.

Catch-all handling

Catch-all acceptance is evidence, not proof

A domain that accepts random local parts can hide invalid recipients. WillItInbox marks that as risky instead of pretending every accepted RCPT response proves an individual mailbox exists.

What it proves

The receiving domain may accept many or all local parts at SMTP time.

What it does not prove

It does not prove the person exists, will engage, or will avoid a later bounce.

What to do

Segment catch-all addresses, confirm high-value leads, and avoid treating them as guaranteed safe volume.

Product workflows

Single, bulk, and API validation share the same policy model

Use one evidence model across every place an address enters your business. That keeps signup forms, CSV imports, outbound systems, and internal tools from arguing about what an address means.

Single check

Use /validator for signup, lead capture, support, and admin workflows that need an immediate status.

Bulk CSV hygiene

Use /validator/bulk to clean imports, reactivation lists, and campaign files without losing original row context.

API automation

Use /solutions/email-validation-api when validation needs to run inside product, CRM, enrichment, or QA systems.

Sample result card

A useful result tells the next system what to do

The page should help a buyer picture the output before they sign up. Store the verdict, reason, confidence, evidence, and policy action separately.

Field	Example	Why it matters
status	risky	The top-level policy bucket for product and growth systems.
reason	catch_all_domain	The specific signal that explains the status.
confidence	medium	Whether the evidence is strong enough for automation.
evidence	mx_present, smtp_accepted_random_local, role=false	The audit trail for support, sales ops, and engineering.
recommended_action	segment_or_confirm	The operational next step.

Suppression policy

Turn validation into list hygiene, not just a one-off lookup

A strong validator helps the team decide what should enter the product, what should be suppressed, what should be retried, and what needs a lower-risk campaign path.

Input type	Default action	Best next link
Invalid	Suppress and record the reason.	/docs/email-validation
Risky	Segment by catch-all, role, disposable, or confidence.	/validator/bulk
Unknown	Retry or wait for follow-up evidence before a high-volume send.	/docs/bulk-validation
Valid	Accept, then test the actual message before important sends.	/tools/email-deliverability-tester